buildout.py: Deserialize text on section:option access

src/zc/buildout/buildout.py

@@ -1550,6 +1550,12 @@ class Options(DictMixin):
                 else:
                     raise MissingOption("Referenced option does not exist:",
                                         section, option)
+            else:
+                # As it is safe to deserialize text, try to do so
+                if hasattr(v, 'startswith') and v.startswith(SERIALISED_VALUE_MAGIC):
+                  new_v = loads(v)
+                  if isinstance(new_v, text_type):
+                      v = new_v
             subs.append(v)
         subs.append('')